We synthesize fragments of complex polysaccharides that are part of bacterial pathogens and study their binding with antibodies. We then identify immunodominant epitopes in said polysaccharides, and prepare glycosides thereof bearing aglycons suitable for linkage to proteins. After conjugation to suitable carriers, we evaluate the neoglycoconjugates obtained as synthetic vaccines against infectious diseases caused by these bacterial pathogens. In continuation of our work on synthesis of immunogens for Vibrio cholerae O:1 antibodies, we have developed new agents for linking carbohydrates to proteins, and used them to prepare neoglycoconjugates. Before conjugating the precious, linker- equipped, synthetic fragments of the O-PS ofVibrio cholerae O:1, we have undertaken a detailed study aimed at optimizing the reaction conditions. The effect of variables, such as concentration of the hapten, molar ratio of the hapten used to the number of reactive groups in the chicken serum albumin (CSA, used as a model carrier protein), and the reaction time upon the incorporation of the hapten has been evaluated. In these experiments, derivatives of D-glucose, equipped with the same linker as the Vibrio cholerae O:1 saccharides to be conjugated were used as haptens. When the hapten representing the immunodominant epitope of the O-PS of Vibrio cholerae O:1 was conjugated to CSA, the incorporation observed was in a remarkable agreement with that expected based on the results of model experiments. The conjugation occurred with high efficiency, and it appears that we can achieve a predicted degree of incorporation of carbohydrate antigens to proteins. This is particularly important in synthetic vaccine development when linking to protein carriers of a defined amount of a precious, synthetic antigen may be required.